Modpack version
1.67d

Can the issue be reproduced?
Yes

Logs
https://pastebin.com/xjipsjgt

Issue
I'm just trying to Boot my server upafter i update it from 1.65a

Please remove the mod Phosphor and try again :)

Encountered this as well. Removing Phosphor does resolve the issue and allow the client to start. However, per https://github.com/jellysquid3/Phosphor/issues/15, the issue is that there are two different mods using SpongeForge, one of which is using an older version of Mixins and preventing Phosphor from loading. It would be good to identify which mod this is (Phosphor dev suggests removing mods until you identify it, which ugh, but would work) and see if it can be updated (or else weigh its contribution to the modpack vs the benefits Phosphor provides)

Edit: Forgot that I had a few extra mods installed (Flux Networks, Lapis Stays In Enchanting Table, Tinker I/O, Tinkers Complement), as well as Optifine. Starting with a clean install of 1.67d did not show the issue. As will come as a surprise to probably no one, Optifine was the issue. Upgrading to the latest version of Optifine for 1.12.2 (HD_U_E3) seems to have resolved the crash on start issue for me.

soo i remove the mod and this happy https://pastebin.com/JsiaGtjA

Pastebin

[Apache Log] after i remove the mod - Pastebin.com

Encountered this as well. Removing Phosphor does resolve the issue and allow the client to start. However, per jellysquid3/Phosphor#15, the issue is that there are two different mods using SpongeForge, one of which is using an older version of Mixins and preventing Phosphor from loading. It would be good to identify which mod this is (Phosphor dev suggests removing mods until you identify it, which ugh, but would work) and see if it can be updated (or else weigh its contribution to the modpack vs the benefits Phosphor provides)

I'm need to stay in the sam modlist as Niller make this mods as it's a Server i'm Host for People soo

Removing SpongeForge would also solve your issue.

this is not a Sponge or Phosphor issue, see TeamWizardry/LibrarianLib#77 TeamWizardry/LibrarianLib#99
LibrarianLib breaks with anything that uses Mixin

If an issue is only present when SpongeForge is also present, I call it a SpongeForge issue. I'm not saying it's caused by SpongeForge. Either way, looks like it'll be fixed in the upcoming release of LibrarianLib.

no, it also happens with other mods that use mixin like phosphor or laggoggles, so you don't need SpongeForge for it to happen

I hope soo course my servers use it for all the things

no, it also happens with other mods that use mixin like phosphor or laggoggles, so you don't need SpongeForge for it to happen

Not true, I've been running Lag Goggles with it. It only happens with specific mixin targets it seems.
Again, we're working on fixing this, but our main ASM guy is not very active atm (and no one could help when asking on the sponge discord directly).